“I have achieved everything I dreamed of, and now I want to start my second career after sports. I would have never imagined that I would have such a long and incredibly successful boxing career,” Klitschko said.

Joshua will not fight Bulgarian mandatory challenger Kubrat Pulev before December 2 or risk being stripped of his IBF belt.

Klitschko held the WBA, IBF, and WBO from 2006 to 2015, when he lost to Tyson Fury.

He ends his career with 64 wins and 5 losses.

The former champion turned professional in 1996, after winning the super-heavyweight Olympic gold medal in Atlanta.